At around 10 o'clock on Friday evening I received a call from a prominent figure in the Jewish community, a lifelong Labour supporter who had worked for the party in his youth.

The count for the London mayoral election was looking closer than anyone had predicted and my caller was getting twitchy.

"It's horrible wanting the Labour candidate to lose, but I just can't bear the thought of him winning," he said.

Calls like this were being made across the Jewish community as the gap between the leading candidates narrowed. For a moment, the prospect of an astonishing last-minute Ken Livingstone-comeback looked like a real possibility, and people were beginning to get genuinely fearful.

Relations between Mr Livingstone and the Jewish community have never been more than cordial, but his ill-judged comments suggesting that Jews were too rich to vote Labour, made at a private dinner during the campaign, marked a new low. In Jewish Labour circles there was a simmering fury. Kate Bearman, the former director of Labour Friends of Israel, captured the views of many when she tweeted on Friday evening: "praying Ken's lost and actually worrying he hasn't. So angry with Labour", and followed up with: "tight or not tight, Labour supporters should not be put in this position. By their own party."

Mr Livingstone has always been convinced that the Jewish establishment, led by the Board of Deputies, was out to get him. With the results so close, could it be that is really was "the Jews wot won it" for Boris Johnson?

Until the ward by ward results come in, it will be difficult to answer this question. And even then, without seeing into the mind of every Jewish voter, it is impossible to be definitive. In the Barnet and Camden constituency, the results certainly look stark, with a 10 percentage point difference between people who voted Labour in the London Assembly election and those who voted for a Labour mayor. But even here the situation is complicated by local factors: the unpopularity of Conservative Assembly candidate Brian Coleman, and a phenomenally unpopular parking scheme brought in by Tory Barnet Council.

What is undeniable, however, is that if London's liberal-leaning Jewish community had chosen to vote Labour, then they could have delivered the election for Mr Livingstone. In his comments to the private meeting, brokered by the London Jewish Forum, this is something the Labour candidate clearly failed to understand. Demonstrating a staggering ignorance of historical voting patterns, he did not realise that the Jewish community is an exception to his rule that the wealthier you get, the more likely you are to vote Tory.

Ken Livingstone's alienation of London's Jewish community was quite simply suicidal. As Bicom campaigns director and Labour NEC member Luke Akehurst wrote on the Labour List blog: "This must rank as one of the most bizarre electoral tactics any candidate in the democratic world has ever employed – deliberately shunning a group of 120,000 voters, with a high propensity to turnout and a known record as a swing vote."

Mr Livingstone has been characteristically divisive, even in defeat. Mr Akehurst was denounced as peddling "Blairite claptrap" for suggesting that the choice of Mr Livingstone as the Labour candidate was disastrous. The spin from the Livingstone camp was that Boris Johnson was unbeatable and only their man could have got as close as he did. It has been argued that in London overall there was only a one percentage point difference between the Labour vote for mayor and the Labour vote for the GLA. But this fails to take into account the substantial numbers of left-leaning voters who chose to vote for smaller parties in the GLA elections, but did not vote for Mr Livingstone for mayor.

This week Jewish Labour activist Andrew Gilbert, who signed a letter endorsing Mr Livingstone in the run-up to the election, circulated figures suggesting there was a six - eight per cent "Ken drag-factor" in the election, despite the major national swing to Labour.

Neil Nerva from the Jewish Labour Movement, who also signed the letter endorsing Ken Livingstone's candidacy, added: "The big swing to Labour in the elections for the London Assembly meant Labour now had 12 seats, an increase of 50 per cent. Andrew Dismore's great result in Barnet Camden showed that Labour in London can win the votes of Jewish electors. It was disappointing that voters had not had the confidence to deliver the same swing to Ken Livingstone - the Labour mayoral candidate."

There are those within the Labour Party leadership who will be hugely relieved that Ken Livingstone was defeated on May 3. Six months ago, the circle around Ed Miliband had all but written off the mayoral election as a lost cause, but were forced to rethink, after the meltdown of support for the coalition led to a narrowing of the polls.

But it is too early to write off Mr Livingstone or his brand of politics as a spent force. He remains deeply influential in certain Labour circles. He serves the Labour NEC and is standing for election again this year.

His legacy will continue through Simon Fletcher, who ran his campaign and will now be looking for a job within the Labour Party.

One interesting result of the swing to Labour is the election to the GLA of Tom Copley, a youthful ally of Mr Livingstone thought to be instrumental in persuading the Labour candidate to "apologise" to the Jewish community in the pages of the JC. As a former employee of Searchlight, Mr Copley has a good anti-racist pedigree and there is some hope that he will help temper attitudes on the left of the party.

And then there is the small matter of the man who won the London mayoral election. While the Jewish community has been focused on the Livingstone issue, there has been little time to ask what Boris Johnson intends to do for social cohesion in the capital, how he will address the concerns of the Jewish community and how he will learn from it as London's most established minority.

Mr Johnson has benefited hugely from the distraction provided by his opponent's "Jewish problem" and now he will need to be held to account.